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Since the Scoliosis Research Society released a report on cord injury related to Harrington rod instrumentation for scoliosis, little has been published on the pathophysiology of this disorder. Dolan et al. (4) described diminished cord blood flow associated with spinal distraction in a cat model, but failed to demonstrate its cause. In this article, we describe a series of in vitro experiments performed on dog and sheep cadaver spinal cords. Controlled distractive forces were applied to spinal cords while monitoring both cord interstitial pressure and cord elongation. A close (Ravg = 0.986) correlation was noted between applied tensile forces and cord interstitial pressure. At 1,000-g loads, the average tissue pressure obtained was 29.5 cm H2O, ranging from 17 to 47 cm H2O. However, it was noted that the cord demonstrated nonlinear tensile elastic properties that appeared exponential in the range examined. These properties are consistent with those described for collagen-containing compounds. We conclude that spinal cord distraction is capable of generating cord tissue pressures that could cause a spinal cord compartment syndrome and thereby seriously impair spinal cord blood flow causing spinal cord injury.

Angiolipomas of the central nervous system are rare tumors (37 cases in the literature) and are mostly located in the spine (95%), rarely in the skull. When they are intraspinal, these masses are extradural in more than 90% of the cases. Angiolipomas are benign tumors containing vascular and mature adipose elements. The clinical symptomatology is non specific, but computed tomography and mostly MRI provide a precise diagnosis. With 2 additional cases and a review of the literature, we define the main characteristics of these tumors.

The cranio-encephalic epidermoid cysts are rare tumors. These lesions are extra-axial and can occur at the infratentorial or supratentorial level. The epidermoid cysts are classically in contact with the base of the skull, and less often intraventricular; the other locations are exceptional. Because of their CT aspect (hypodense lesion, rarely isodense, well defined, without contrast enhancement, and without surrounding edema) and MR aspect (in more than 70% of the cases: more or less homogeneous lesion, hypointense in T1 and hyperintense in T2), the authors believe that it is possible to suggest such a diagnosis even with an atypically located case. We report the case of an epidermoid cyst located between the corpus callosum and the falx cerebri.

Plasma diatrizoate concentrations during computed cranial tomography were measured by UV spectrophotometry in 14 patients. A loading dose of 0.82 mg diatrizoate/kg followed by a stead infusion of 0.01 mg/kg was required to attain and maintain plasma concentrations of approximately 400 mg/100 ml. Lowering the beam energy resulted in a substantial increase in the EMI numbers of diatrizoate and significant improvement in the delineation of contrast containing lesions. A contrast index estimating the volume of pixel containing diatrizoate was calculated for five diagnosed lesions and this factor appears to be related to vascularity and extravasation.

During a two year period, March 1977 to April 1979, a total of 92 bovine abortions were studied. The cause of abortion was determined in 34.8% of the cases examined. Opportunistic bacteria, the most commonly diagnosed cause of abortion, accounted for 31.2% of the cases. Leptospirosis was associated with 28.1% of the abortions, infectious bovine rhinotracheitis and fungi in respectively 15.7%, bovine viral diarrhea in 6.2%. A congenital abnormality accounted for one case (3.1%). In 23 cases (25%), there was no definitive diagnosis, in spite of evidence of experience with pathogen or suggestive findings of pathology, but insufficient evidence to warrant diagnosis. No findings were recorded in 35.8% of the (possibly noninfectious) cases and in only four cases (4.4%), specimens were unsatisfactory for examination.